use mattdm/fedora in fedora doc and other cosmetic changes

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
yum upgrade on fedora not required before install

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
add unofficial header back, yum update docker

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
separate block for yum update docker

Signed-off-by: Lokesh Mandvekar <lsm5@redhat.com>
Merge pull request #3071 from lsm5/fedora-docs-update

use mattdm/fedora in fedora doc and other cosmetic changes